2020-12-01 19:05:12

by Amjad Ouled-Ameur

Subject: [PATCH v2 1/3] phy: amlogic: phy-meson-gxl-usb2: fix shared reset controller use

Use reset_control_rearm() call if an error occurs in case
phy_meson_gxl_usb2_init() fails after reset() has been called ; or in case
phy_meson_gxl_usb2_exit() is called i.e the resource is no longer used
and the reset line may be triggered again by other devices.

reset_control_rearm() keeps use of triggered_count sane in the reset
framework. Therefore, use of reset_control_reset() on shared reset line
should be balanced with reset_control_rearm().

Signed-off-by: Amjad Ouled-Ameur <[email protected]>
Reported-by: Jerome Brunet <[email protected]>
---
changes since v1: [1]
* Moved reset_control_rearm after clk_disable_unprepare to clean things up
in reverse order of initialization for phy: amlogic: meson drivers

IMPORTANT:
This patchset depends on this patch [2], it adds reset_control_rearm() call
to the reset framework API, it has been approved by the maintainer, and
will be applied to reset/next

There is currently an immutable branch with it [3]

[1]: https://lore.kernel.org/lkml/[email protected]/
[2]: https://lore.kernel.org/lkml/[email protected]/
[3]: git://git.pengutronix.de/git/pza/linux.git reset/shared-retrigger

drivers/phy/amlogic/phy-meson-gxl-usb2.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/amlogic/phy-meson-gxl-usb2.c b/drivers/phy/amlogic/phy-meson-gxl-usb2.c
index 43ec9bf24abf..1ddf5e5e4184 100644
--- a/drivers/phy/amlogic/phy-meson-gxl-usb2.c
+++ b/drivers/phy/amlogic/phy-meson-gxl-usb2.c
@@ -114,8 +114,10 @@ static int phy_meson_gxl_usb2_init(struct phy *phy)
return ret;

ret = clk_prepare_enable(priv->clk);
- if (ret)
+ if (ret) {
+ reset_control_rearm(priv->reset);
return ret;
+ }

return 0;
}
@@ -125,6 +127,7 @@ static int phy_meson_gxl_usb2_exit(struct phy *phy)
struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);

clk_disable_unprepare(priv->clk);
+ reset_control_rearm(priv->reset);

return 0;
}
--
2.17.1

2020-12-05 21:58:24

by Martin Blumenstingl

Subject: Re: [PATCH v2 1/3] phy: amlogic: phy-meson-gxl-usb2: fix shared reset controller use

On Tue, Dec 1, 2020 at 8:01 PM Amjad Ouled-Ameur
<[email protected]> wrote:
>
> Use reset_control_rearm() call if an error occurs in case
> phy_meson_gxl_usb2_init() fails after reset() has been called ; or in case
> phy_meson_gxl_usb2_exit() is called i.e the resource is no longer used
> and the reset line may be triggered again by other devices.
>
> reset_control_rearm() keeps use of triggered_count sane in the reset
> framework. Therefore, use of reset_control_reset() on shared reset line
> should be balanced with reset_control_rearm().
>
> Signed-off-by: Amjad Ouled-Ameur <[email protected]>
> Reported-by: Jerome Brunet <[email protected]>
Reviewed-by: Martin Blumenstingl <[email protected]>